Capecitabine in the Treatment of Breast Cancer With Low-hormone Receptor Expression After Neoadjuvant Chemotherapy

The investigators will recruit patients who had low- hormone receptor (HR)positive breast cancer of stage I - IIIC and pathologically assessed residual cancer cells (no pathological complete response, non-pCR) after neoadjuvant chemotherapy with anthracycline, taxane, or both. Participants who have residual components of ductal carcinoma in situ are assessed as having a pathological complete response. Participants with tumor-positive lymph nodes excluded. Other key eligibility criteria are low- hormone receptor (HR)positive, including low-ER and low-PR, low-ER and PR-negative, low-PR and ER-negative. The definition of low hormone receptor (HR) positive is nuclear staining of 1%-10% of the epithelial component of the tumor. Eligible participants are centrally enrolled after pathological assessment and are randomly assigned in a 1:1 ratio to receive either capecitabine plus standard therapy or standard therapy alone (control). The trial treatments are standard postsurgical treatments, which included endocrine therapy in participants with estrogen-receptor-positive (nuclear staining ≥ 1%) disease, targeted therapy in participants with HER-2 overexpression and radiotherapy (if indicated), with or without capecitabine. After surgery, the capecitabine group receive oral capecitabine (at a dose of 1250 mg per square meter of body-surface area, twice per day, on days 1 to 14) every 3 weeks for eight cycles. The concomitant administration of postsurgical endocrine therapy is allowed. Postsurgical radiotherapy could be given before or after randomization and could be concomitant with postsurgical endocrine therapy.